root / lib / http / client.py @ 7260cfbe
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# Copyright (C) 2007, 2008 Google Inc.
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful, but
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# WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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# General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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# 02110-1301, USA.
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"""HTTP client module.
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"""
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# pylint: disable-msg=E1103
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# # E1103: %s %r has no %r member (but some types could not be
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# inferred), since _socketobject could be ssl or not and pylint
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# doesn't parse that
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import os |
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import select |
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import socket |
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import errno |
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import threading |
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from ganeti import workerpool |
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from ganeti import http |
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HTTP_CLIENT_THREADS = 10
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class HttpClientRequest(object): |
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def __init__(self, host, port, method, path, headers=None, post_data=None, |
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ssl_params=None, ssl_verify_peer=False): |
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"""Describes an HTTP request.
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@type host: string
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@param host: Hostname
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@type port: int
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@param port: Port
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@type method: string
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@param method: Method name
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@type path: string
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@param path: Request path
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@type headers: dict or None
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@param headers: Additional headers to send
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@type post_data: string or None
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@param post_data: Additional data to send
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@type ssl_params: HttpSslParams
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@param ssl_params: SSL key and certificate
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@type ssl_verify_peer: bool
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@param ssl_verify_peer: Whether to compare our certificate with
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server's certificate
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"""
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if post_data is not None: |
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assert method.upper() in (http.HTTP_POST, http.HTTP_PUT), \ |
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"Only POST and GET requests support sending data"
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assert path.startswith("/"), "Path must start with slash (/)" |
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# Request attributes
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self.host = host
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self.port = port
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self.ssl_params = ssl_params
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self.ssl_verify_peer = ssl_verify_peer
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self.method = method
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self.path = path
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self.headers = headers
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self.post_data = post_data
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self.success = None |
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self.error = None |
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# Raw response
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self.response = None |
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# Response attributes
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self.resp_version = None |
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self.resp_status_code = None |
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self.resp_reason = None |
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self.resp_headers = None |
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self.resp_body = None |
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class _HttpClientToServerMessageWriter(http.HttpMessageWriter): |
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pass
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class _HttpServerToClientMessageReader(http.HttpMessageReader): |
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# Length limits
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START_LINE_LENGTH_MAX = 512
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HEADER_LENGTH_MAX = 4096
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def ParseStartLine(self, start_line): |
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"""Parses the status line sent by the server.
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"""
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# Empty lines are skipped when reading
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assert start_line
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try:
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[version, status, reason] = start_line.split(None, 2) |
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except ValueError: |
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try:
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[version, status] = start_line.split(None, 1) |
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reason = ""
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except ValueError: |
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version = http.HTTP_0_9 |
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if version:
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version = version.upper() |
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# The status code is a three-digit number
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try:
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status = int(status)
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if status < 100 or status > 999: |
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status = -1
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except ValueError: |
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status = -1
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if status == -1: |
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raise http.HttpError("Invalid status code (%r)" % start_line) |
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return http.HttpServerToClientStartLine(version, status, reason)
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class HttpClientRequestExecutor(http.HttpBase): |
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# Default headers
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DEFAULT_HEADERS = { |
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http.HTTP_USER_AGENT: http.HTTP_GANETI_VERSION, |
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# TODO: For keep-alive, don't send "Connection: close"
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http.HTTP_CONNECTION: "close",
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} |
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# Timeouts in seconds for socket layer
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# TODO: Soft timeout instead of only socket timeout?
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# TODO: Make read timeout configurable per OpCode?
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CONNECT_TIMEOUT = 5
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WRITE_TIMEOUT = 10
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READ_TIMEOUT = None
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CLOSE_TIMEOUT = 1
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def __init__(self, req): |
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"""Initializes the HttpClientRequestExecutor class.
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@type req: HttpClientRequest
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@param req: Request object
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"""
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http.HttpBase.__init__(self)
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self.request = req
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try:
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# TODO: Implement connection caching/keep-alive
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self.sock = self._CreateSocket(req.ssl_params, |
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req.ssl_verify_peer) |
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# Disable Python's timeout
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self.sock.settimeout(None) |
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# Operate in non-blocking mode
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self.sock.setblocking(0) |
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response_msg_reader = None
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response_msg = None
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force_close = True
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self._Connect()
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try:
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self._SendRequest()
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(response_msg_reader, response_msg) = self._ReadResponse()
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# Only wait for server to close if we didn't have any exception.
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force_close = False
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finally:
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# TODO: Keep-alive is not supported, always close connection
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force_close = True
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http.ShutdownConnection(self.sock, self.CLOSE_TIMEOUT, |
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self.WRITE_TIMEOUT, response_msg_reader,
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force_close) |
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self.sock.close()
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self.sock = None |
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req.response = response_msg |
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req.resp_version = req.response.start_line.version |
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req.resp_status_code = req.response.start_line.code |
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req.resp_reason = req.response.start_line.reason |
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req.resp_headers = req.response.headers |
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req.resp_body = req.response.body |
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req.success = True
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req.error = None
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except http.HttpError, err:
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req.success = False
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req.error = str(err)
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def _Connect(self): |
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"""Non-blocking connect to host with timeout.
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"""
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connected = False
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while True: |
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try:
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connect_error = self.sock.connect_ex((self.request.host, |
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self.request.port))
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except socket.gaierror, err:
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raise http.HttpError("Connection failed: %s" % str(err)) |
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if connect_error == errno.EINTR:
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# Mask signals
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pass
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elif connect_error == 0: |
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# Connection established
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connected = True
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break
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elif connect_error == errno.EINPROGRESS:
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# Connection started
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break
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raise http.HttpError("Connection failed (%s: %s)" % |
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(connect_error, os.strerror(connect_error))) |
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if not connected: |
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# Wait for connection
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event = http.WaitForSocketCondition(self.sock, select.POLLOUT,
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self.CONNECT_TIMEOUT)
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if event is None: |
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raise http.HttpError("Timeout while connecting to server") |
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# Get error code
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connect_error = self.sock.getsockopt(socket.SOL_SOCKET, socket.SO_ERROR)
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if connect_error != 0: |
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raise http.HttpError("Connection failed (%s: %s)" % |
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(connect_error, os.strerror(connect_error))) |
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# Enable TCP keep-alive
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self.sock.setsockopt(socket.SOL_SOCKET, socket.SO_KEEPALIVE, 1) |
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# If needed, Linux specific options are available to change the TCP
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# keep-alive settings, see "man 7 tcp" for TCP_KEEPCNT, TCP_KEEPIDLE and
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# TCP_KEEPINTVL.
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# Do the secret SSL handshake
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if self.using_ssl: |
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self.sock.set_connect_state() # pylint: disable-msg=E1103 |
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try:
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http.Handshake(self.sock, self.WRITE_TIMEOUT) |
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except http.HttpSessionHandshakeUnexpectedEOF:
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raise http.HttpError("Server closed connection during SSL handshake") |
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def _SendRequest(self): |
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"""Sends request to server.
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"""
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# Headers
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send_headers = self.DEFAULT_HEADERS.copy()
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if self.request.headers: |
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send_headers.update(self.request.headers)
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send_headers[http.HTTP_HOST] = "%s:%s" % (self.request.host, |
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self.request.port)
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# Response message
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msg = http.HttpMessage() |
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# Combine request line. We only support HTTP/1.0 (no chunked transfers and
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# no keep-alive).
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# TODO: For keep-alive, change to HTTP/1.1
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msg.start_line = \ |
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http.HttpClientToServerStartLine(method=self.request.method.upper(),
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path=self.request.path,
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version=http.HTTP_1_0) |
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msg.headers = send_headers |
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msg.body = self.request.post_data
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try:
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_HttpClientToServerMessageWriter(self.sock, msg, self.WRITE_TIMEOUT) |
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except http.HttpSocketTimeout:
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raise http.HttpError("Timeout while sending request") |
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except socket.error, err:
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raise http.HttpError("Error sending request: %s" % err) |
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def _ReadResponse(self): |
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"""Read response from server.
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"""
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response_msg = http.HttpMessage() |
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try:
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response_msg_reader = \ |
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_HttpServerToClientMessageReader(self.sock, response_msg,
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self.READ_TIMEOUT)
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except http.HttpSocketTimeout:
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raise http.HttpError("Timeout while reading response") |
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except socket.error, err:
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raise http.HttpError("Error reading response: %s" % err) |
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return (response_msg_reader, response_msg)
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class _HttpClientPendingRequest(object): |
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"""Data class for pending requests.
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"""
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def __init__(self, request): |
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self.request = request
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# Thread synchronization
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self.done = threading.Event()
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class HttpClientWorker(workerpool.BaseWorker): |
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"""HTTP client worker class.
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"""
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def RunTask(self, pend_req): # pylint: disable-msg=W0221 |
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try:
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HttpClientRequestExecutor(pend_req.request) |
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finally:
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pend_req.done.set() |
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class HttpClientWorkerPool(workerpool.WorkerPool): |
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def __init__(self, manager): |
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workerpool.WorkerPool.__init__(self, HTTP_CLIENT_THREADS,
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HttpClientWorker) |
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self.manager = manager
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class HttpClientManager(object): |
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"""Manages HTTP requests.
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"""
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def __init__(self): |
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self._wpool = HttpClientWorkerPool(self) |
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def __del__(self): |
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self.Shutdown()
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def ExecRequests(self, requests): |
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"""Execute HTTP requests.
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This function can be called from multiple threads at the same time.
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@type requests: List of HttpClientRequest instances
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@param requests: The requests to execute
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@rtype: List of HttpClientRequest instances
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@return: The list of requests passed in
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"""
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# _HttpClientPendingRequest is used for internal thread synchronization
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pending = [_HttpClientPendingRequest(req) for req in requests] |
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try:
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# Add requests to queue
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for pend_req in pending: |
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self._wpool.AddTask(pend_req)
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finally:
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# In case of an exception we should still wait for the rest, otherwise
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# another thread from the worker pool could modify the request object
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# after we returned.
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# And wait for them to finish
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for pend_req in pending: |
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pend_req.done.wait() |
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# Return original list
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return requests
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def Shutdown(self): |
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self._wpool.Quiesce()
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self._wpool.TerminateWorkers()
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